Intervertebral implant

ABSTRACT

An intervertebral implant for being implanted between adjacent vertebrae is provided. The implant includes a generally elongate implant body having a length extending between opposite longitudinal ends thereof, a superior face and an inferior face. The superior face and inferior face include cortical teeth adjacent to the implant body longitudinal ends. Additionally, the superior and inferior faces include longitudinally central teeth intermediate the cortical teeth and have bone engaging ends. The central teeth have a sharper configuration than that of the cortical teeth bone engaging ends for biting into the softer central bone material of the vertebrae. The cortical teeth are arranged in a first density per unit area and the central teeth are arranged in a second density per unit area that is less than the first density.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of prior application Ser. No.16/228,858, filed Dec. 21, 2018, which is a continuation of priorapplication Ser. No. 15/886,164, filed Feb. 1, 2018, now U.S. Pat. No.10,182,920, issued Jan. 22, 2019, which is a continuation of priorapplication Ser. No. 15/176,707, filed Jun. 8, 2016, now U.S. Pat. No.9,883,949, issued Feb. 6, 2018, which is a continuation of priorapplication Ser. No. 14/734,764, filed Jun. 9, 2015, now U.S. Pat. No.9,387,092, issued Jul. 12, 2016, which is a continuation of priorapplication Ser. No. 13/648,086, filed Oct. 9, 2012, now U.S. Pat. No.9,132,021, issued Sep. 15, 2015, which claims benefit of U.S.Provisional Application No. 61/545,030, filed Oct. 7, 2011, which arehereby incorporated herein by reference in their entirety.

FIELD

The present application relates to implant devices for implantationbetween adjacent vertebrae and, in particular, to implant devices forimmobilization and fusion of adjacent vertebrae.

BACKGROUND

A variety of spinal conditions result in a person experiencing pain orlimited physical activity and ability. More specifically, damage tovertebrae composing the spine and spinal discs between the vertebrae mayoccur as a result of trauma, deformity, disease, or other degenerativeconditions. Some of these conditions can be life-threatening, whileothers cause impingement on the spinal cord resulting in pain and a lackof mobility. Removing the impingement, thus reducing swelling orpressure from the damaged or diseased tissue against the spinal cord,can relieve the pain and often promotes healing and return of normalnervous system functioning. However, the absence of proper medical caremay lead to further damage and degeneration of spinal health and topermanent spinal cord damage.

The spine principally includes a series of vertebrae and spinal discslocated in a space between adjacent vertebrae. The vertebrae are formedof hard bone while the discs comprise a comparatively soft annulus andnucleus. The discs support the vertebrae in proper position and enablethe torso to be rotated and to bend laterally andanteriorly-posteriorly. The discs also act as shock absorbers orcushions when the spine is experiencing shock, such as when a personjogs.

Damage to the spine often results in a reduced physiological capability.For instance, damage to the disc may allow the annulus to bulge,commonly referred to as a herniated disc. In more severe cases, thedamage may allow the nucleus to leak from the annulus. These sameresults may be brought about by a damaged or fractured vertebra. In anyevent, such damage often causes the vertebrae to shift closer orcompress, and often causes a portion of the disc to press against thespinal cord.

One manner of treating these conditions is through immobilization of thevertebrae in a portion of the spine, such as two or more adjacentvertebrae. The conditions often lead to degeneration and a loss of discsupport, and immobilization is often beneficial in reducing oreliminating pain. Immobilization and/or fusion have been performed via anumber of techniques and devices, and the type of injury often suggestsa preferred treatment regime.

One of these treatments is known as spinal fusion surgery. For this, twoor more adjacent or consecutive vertebrae are initially immobilizedrelative to each other and, over time, become fused in a desired spatialrelationship. The vertebrae are relatively immobilized at the properintervertebral distance which replicates the support characteristics ofthe spine. This prescription sacrifices the rotation or flexion betweenthe affected vertebrae, such that some loss of movement and flexibilityis experienced. However, the compression on the spinal cord due to theinjury or damage is reduced or eliminated, and the fused vertebraeprotect the spine and spinal cord from injury. Overall, the non-fusedportions of the spine are largely able to compensate for most normalmovement expected by a patient.

Currently, a number of vertebral body replacement devices (VBRs) forimmobilizing and fusing adjacent vertebrae are known. During animplantation procedure, the intervertebral space is initially excavatedto provide a volume for locating a VBR therein. Once excavated, theadjacent vertebrae have a tendency to shift toward each other a smallamount, thereby compressing the space or volume. Additionally, many VBRshave surface features such as prongs or teeth which extend away fromupper and lower surfaces of the VBR for being embedded into the adjacentvertebrae. In order to locate the device within the intervertebralspace, instruments may be used to spread the vertebrae apart. Duringsuch a procedure, care must be taken not to damage the spinal cord. TheVBRs may then be inserted into the intervertebral space in anorientation where the surfaces with teeth thereon face the adjacentvertebral surfaces. However, the teeth may impede insertion of the VBRby biting into the bone too much. Alternatively, the VBR may not bemaintained in position if the teeth do not bite into the bone enough toimpede movement or walking of the VBR when installed.

Further, oftentimes spacing between vertebrae is not uniform such thatdifferently shaped VBRs may be inserted. In this regard, it may bepossible that two vertebrae have a large gap on the patient's right sidewhile two other vertebrae in the same patient may have a large gap onthe patient's left side. In such situations, where lateral insertion ofthe VBR is being used, the surgeon must go in on opposite sides of thepatient or otherwise rotate the patient to insert the VBRs in betweenthe oppositely shaped sets of vertebrae. This is a result of a number offeatures such as the shape of the VBRs and the location of the toolcoupling locations.

In some cases, the intervertebral space receives the VBR or implantdevice as well as an amount of graft material. The graft material may bein a number of forms, such as cancellous bone chips, which are packedinto the intervertebral space and around the VBR. For VBRs with internalcavities opening on at least one side to the intervertebral space, graftmaterial is also placed within the cavities so that bone may growthrough the VBR device and join with bone formation throughout theintervertebral space.

However, as these bone chips are loose and oftentimes fragile, migrationof the bone chips from the intervertebral space presents an issue. Whileimplanting more bone graft material promotes faster bone formationthroughout the intervertebral space, the loose bone chips or graftmaterial portions tend to separate from each other, a tendency which isexacerbated by being more tightly packed. Full fusion may take upwardsof two years, during which time a patient's movement may contribute tothe graft material explanting from the intervertebral site. In general,previous solutions to this problem have consisted of sewing theintervertebral site closed, such as by retaining and re-closing thenatural damaged annulus, or by providing the cavities within a VBR.

Accordingly, there has been a need for improved spinal fusion systems.

SUMMARY

Thus, in accordance with one form, an intervertebral implant for beingimplanted between adjacent vertebrae is provided. The implant includes agenerally elongate implant body having a length extending betweenopposite longitudinal ends thereof, a superior face and an inferiorface. The superior face and inferior face include cortical teethadjacent to the implant body longitudinal ends and have bone-engagingends for engaging outer cortical bone material of the vertebrae.Additionally, the superior and inferior faces include longitudinallycentral teeth intermediate the cortical teeth and have bone engagingends for engaging central bone material of the vertebrae that are softerthan the cortical bone material thereof with the central teeth boneengaging ends having a sharper configuration than that of the corticalteeth bone engaging ends for biting into the softer central bonematerial of the vertebrae.

In accordance with one form, an intervertebral implant is providedhaving an implant body. A superior face of the implant body includes afirst end, a second end and a central portion positioned between thefirst and second ends. An inferior face of the implant body includes afirst end, a second end and a central portion positioned between thefirst and second ends. Different cortical and central teeth on at leastone of the superior and inferior faces are configured in anosteo-specific arrangement with at least one of the first and secondends including a first density of the cortical teeth per unit area andthe central portion including a second density of the central teeth perunit area, the first density being greater than the second density.

According to one form, an intervertebral implant for insertion betweenadjacent vertebrae is provided. The intervertebral implant includes agenerally elongate implant body having a length extending betweenopposite longitudinal ends thereof. Further, a thick body portion islocated at one of the implant body ends and has a first insertion toolattachment portion. A thin body portion is at the other implant body endso that the implant body generally tapers down from the one end to theother end thereof. A longitudinal gap in located the thin body portionopen to the other end of the implant body for receiving an insertiontool therein. A transverse wall portion of the implant body isintermediate the longitudinal ends thereof with the longitudinal gapterminating at the transverse wall portion. Additionally, the transversewall portion has a thickness greater than the thin body portion. Asecond insertion tool attachment portion of the transverse wall portionis provided to which an insertion tool received in the longitudinal gapcan be attached for inserting the implant body either utilizing thefirst insertion tool attachment with the thin body portion leadingduring implant insertion or utilizing the second insertion toolattachment portion with the thick body portion leading during implantinsertion.

An intervertebral implant is provided for insertion between adjacentvertebrae. The implant includes an implant body having a lengthextending between opposite longitudinal ends thereof. Further, theimplant includes a superior face of the implant body and an inferiorface of the implant body. A throughbore extends between the superior andinferior faces through the body and is configured to receive fusionmaterial therein. The implant also includes an interior wall of theimplant body extending along the throughbore and is configured to retainthe fusion material therein. A plurality of first stabilizingprotrusions extend from the interior wall in a first orientation toimpede the fusion material from exiting the aperture to the superiorface during a surgical implant procedure. Further, a plurality of secondstabilizing protrusions extend from the interior wall in a secondorientation to impede fusion material from exiting the aperture to theinferior face during the surgical implant procedure. In this regard, thefirst and second orientations are different.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of one form of an intervertebral implant;

FIG. 2 is a top view of the intervertebral implant of FIG. 1 ;

FIG. 3 is a rear perspective view of the intervertebral implant of FIG.1 ;

FIG. 4 is an enlarged side view of a portion of the intervertebralimplant of FIG. 1 ;

FIG. 5 is a side view of a further intervertebral implant;

FIG. 6 is a cross-sectional view taken along line A-A of FIG. 1 ;

FIG. 7 is an enlarged perspective view of a portion of the cross-sectiontaken along line A-A of FIG. 1 ;

FIG. 8 is an enlarged perspective view of a portion of the cross-sectiontaken along line A-A of FIG. 1 ;

FIG. 9 is a perspective view of one form of an intervertebral implant;

FIG. 10 is a top view of the intervertebral implant of FIG. 9 ;

FIG. 11 is a side view of the intervertebral implant of FIG. 9 ;

FIG. 12 is a rear perspective view of intervertebral implant of FIG. 9 ;

FIG. 13 is a perspective view of an intervertebral implant and insertiontool coupled to one end;

FIG. 14 is an enlarged side view of the intervertebral implant andinsertion tool of FIG. 13 ;

FIG. 15 is an enlarged perspective view of the intervertebral implantand insertion tool of FIG. 13 ;

FIG. 16 is a cross-sectional view taken along line B-B of FIG. 15 ;

FIG. 17 is a perspective view of an intervertebral implant and insertiontool coupled to another end of the intervertebral implant;

FIG. 18 is an enlarged perspective view of the intervertebral implantand insertion tool of FIG. 17 ;

FIG. 19 is a cross-section view taken along line C-C of FIG. 18 ;

FIG. 20 is a side view of two intervertebral implants and insertiontools coupled thereto being inserted between vertebrae; and

FIG. 21 is an enlarged view of the two intervertebral implants andinsertion tools of FIG. 20 .

DETAILED DESCRIPTION

Referring initially to FIG. 1 , one form of an intervertebral implant isshown for implantation within an intervertebral space between adjacentvertebrae, such as used during fusion surgery. More specifically,implant 100 is illustrated as having a body 102, a superior face 104 andan inferior face 106. The superior 104 and inferior 106 faces may have agentle convex curvature to generally match the concave curvature of thevertebrae when installed. These faces may be parallel, or inclined at anangle with respect to each other as will be understood from thedescription and additional embodiments described below and illustratedin the figures.

For example, the implant may be configured in a ‘D’ profile, wedgeprofile, bullet-shaped profile and the like. In one form, the implantmay be configured with profiles comprising a narrower lateral dimensionalong its axis of insertion into the intervertebral space thereinminimizing disruption to tissue. Conversely, since the device must actas a spacer, it must provide adequate support to the superior andinferior endplates of the corresponding vertebrae such that stresses donot cause the device to subside into the endplate bone. Therefore, thedevice should avoid unduly narrow or otherwise unstable profiles withinadequate endplate supporting surfaces. It should be noted that othershapes, sizes and the like are contemplated.

Implant angulation may also be orientated from a shorter first end faceor nose face to a taller second end face or trailing face as in thecoronal taper which will be discussed in more detail regarding otherembodiments described herein. The slope of the implant may be configuredto correct spinal deformities wherein the bone is deformed or diseasedsuch that one side of the intervertebral space is open wider than theother or in which one side of a vertebrae needs to be jacked up in orderto realign a vertebral segment. Moreover, the implant may be angled orbeveled along any respective face or wall to accommodate differentlyshaped vertebrae.

In one form, the body 102 generally includes a length (L) extendingbetween opposite longitudinal ends 112, 114. In one form, thelongitudinal end 112 may be considered generally a nose end while end114 may be considered a tail end. As best seen in FIGS. 1 and 4 , theend 112 may be generally arcuate shaped, beveled or otherwise tapered toassist in distracting adjacent vertebrae during insertion. In thisregard, the end 112 slopes away from or otherwise curves away from therespective superior and inferior faces 104,106. A further implant 115 isshown in FIG. 5 having a more rounded end 117 compared to end 112. Othershapes and sizes of the ends are also contemplated, such as will bedescribed below in further detail with respect to additional embodimentsfound in the figures. The body 102 may also include side walls 116,118,depending on the shape of the body 102.

The implant 100 may include a plurality of different teeth, such ascortical teeth 120 and central teeth 122. The cortical teeth 120 andcentral teeth 122 may be configured and positioned to interact withdifferent bone materials and densities as will be discussed in moredetail below.

As seen in FIGS. 1-3 , in one form, cortical teeth 120 may be positionedon one and/or both of the superior and inferior faces 104,106. Further,the cortical teeth 120 may be positioned adjacent the longitudinal ends112,114 so as to engage outer cortical bone when installed. In thisregard, the cortical teeth 120 may include bone engaging ends 124, suchas peaks of the teeth 120, which are configured for contacting therelatively hard cortical bone material when installed. The bone engagingends 124 need not be sharp as they are configured for contacting thecortical bone. In one form, the bone engaging ends 124 are flattened, asseen in FIG. 8 , or are otherwise rounded or the like to provide contactsurfaces for contacting cortical bone.

The cortical teeth 120 also include valleys 126 between the teeth. Thevalleys 126 may be in the form of grooves, channels and the like to helpseparate and define the individual cortical teeth 120. The valleys 126may also be used to help define a number of different rows 128 ofcortical teeth 120. As shown in FIG. 7 , the cortical teeth 120 may bearranged in a number of rows 128 wherein the rows are generally arrangedin an arcuate manner. In this regard, the arcuate arrangement of thecortical teeth may be configured such that the cortical teeth 120generally conform to the expected location of the cortical bone wheninserted into a patient.

The central teeth 122, on the other hand, include bone engaging ends 130which are relatively sharper when compared to the cortical teeth 120. Asseen in FIGS. 7 and 8 , the bone engaging ends 130 of the cortical teethcome to a much sharper point or peak when compared to the bone engagingends 124 of the cortical teeth 120. In this regard, the central teeth122 may be better suited for biting into the central bone region whichis relatively softer compared to the cortical region. Just as with thecortical teeth 120, the central teeth also include valleys 132 to definethe individual central teeth 122. The valleys 132 may also take avariety of different shapes and sizes. For example, as shown in FIG. 7 ,the valleys 132 are generally bowl shaped to define the bone engagingends 130. In this regard, each valley 132 may be used to define aplurality of different bone engaging ends 130 or peaks. In one form,each valley may be bordered by at least six different peaks or boneengaging ends 130. In this form, the valleys 132 are bowl-like, but arealso generally hexagonal. Other forms, shapes and sizes of the boneengaging ends 130 and valleys 132 are also contemplated.

Further, in one form, the central teeth 122 are more spaced apart fromone another when compared to the cortical teeth 120. More specifically,the bone engaging ends 130 are more spaced from one another than thebone engaging ends 124. In this form, the bone engaging ends 130 of thecentral teeth 122 will be able to provide a greater force per unit areato bite into the softer central bone when compared to the bone engagingends 124 of the cortical teeth biting into the cortical bone area. Inother words, the density (number per unit area) of the cortical teeth120 and/or the bone engaging ends 124 is greater than the density(number per unit area) of the central teeth 122 and/or the bone engagingends 130.

Moreover, in one form, the cortical teeth 120 provide a greater ratio ofcontact surface area, such as the surface area of the bone engaging ends124, per unit area covered by the cortical teeth 120 when compared tothe contact surface area, such as the surface area of the bone engagingends 130, per unit area covered by the central teeth 122. Further, theaverage distance between adjacent engaging ends 124 of the corticalteeth is smaller than the average distance between adjacent engagingends 130 of the central teeth.

The cortical teeth 120 and central teeth 122 may also have varyingheights and otherwise may extend different distances from the respectivefaces 104,106. In one form, the teeth 120,122 extend approximately thesame distance from each of the faces 104,106. In another form, thecentral teeth 122 extend further from the respective faces 104,106 whencompared to the cortical teeth 120. In yet another form, the corticalteeth 120 extend further from the respective faces 104,106 when comparedto the central teeth 122. It should also be understood that the faces104,106 may be curved, tapered and the like such that the teeth 120,122may be relatively flat or may otherwise follow the contour of the faces104,106.

As described above, the cortical teeth 120 and central teeth may beconfigured in a number of different manners to contact specific portionsof bone when inserted into a patient. For example, the cortical teeth120 and central teeth may be configured in an osteo-specific toothpattern. This pattern coincides with the bone type of the intervertebralendplate. The cortical teeth 120 are positioned adjacent denser bone atthe cortical rim of the endplate, whereas the larger and sharper centralteeth 122 reside more centrally where the softer endplate bone islocated. In one form, unlike other devices which may have teethconfigured to prevent implant backout, this osteo-specific toothconfiguration may be utilized to restrict implant movement in alldirections.

The implant 100 may also include one or more throughbores 140 on aninterior wall 142 of the implant body 102. The throughbores 140 may beconfigured to receive bone graft, bone substitute, or other similarmaterial. To assist in maintaining the bone graft, bone substitute, orsimilar material in the throughbore 140, a plurality of stabilizingprotrusions 144 may be included therein. The protrusions 144 may take avariety of forms such as recesses, grooves, bosses, or fins formedwithin the throughbore 140 so as to interfere with packed graft slidingout. As found in the figures, the protrusions 144 are in the form ofridges extended generally around the circumference of the throughbore140. The protrusions 144 are configured to be deep enough to stabilizethe graft yet shallow enough so as to not substantially reduce the sizeof the throughbore 140 therein reducing the strength of the fusion.

In one form, such as shown in FIGS. 7 and 8 , the throughbore 140includes a first plurality of protrusions 146 configured in a firstorientation and a second plurality of protrusions 148 configured in asecond orientation. According to one form, the first and secondprotrusions 146,148 are essentially the same type and form ofprotrusions, simply oriented in different configurations. For example,the first protrusions 146 include an angled surface 150 relative to thesuperior face 104 and a generally parallel face 152 relative to thesuperior face 104. In this regard, the angled surface 150 will permitbone graft material to be inserted from the superior face 104 side ofthe implant 100, but the generally parallel face 152 will impede bonegraft material from exiting the throughbore 140 to the superior face104.

The second plurality of protrusions 148 may include similarly structuredprotrusions, just configured in a generally mirror image manner comparedto the first plurality of protrusions 146. For example, the secondplurality of protrusions 148 may include an angled surface 154 relativeto the inferior face 106 and a generally parallel face 156 relative tothe inferior face 106. The angled surface 154 will permit bone graftmaterial to be inserted from the inferior face 106 side of the implant100, but the generally parallel face 156 will impede bone graft materialfrom exiting the throughbore 140 to the inferior face 106. In one form,the first and second pluralities of protrusions 146,148, are positionedand extend from a midpoint about the longitudinal length of the implant100. In other words, the generally parallel faces 152,156 will bepositioned such that they face the midpoint extending along thelongitudinal axis of the implant.

In one form, such as shown in FIGS. 1 and 2 , the implant 100 mayinclude a plurality of throughbores 140, such as two throughbores 140.However, the implant 100 may include a single throughbore 140 or nothroughbores 140. Further, in the case of multiple throughbores 140, thesizes and shapes of the throughbores 140 need not be the same. Forexample, one throughbore 140 may be wider and longer than anotherthroughbore 140. Similarly, different throughbores 140 may havedifferent heights, extending from the superior face 104 to the inferiorface 106.

Further, the body 102 may include an insertion tool attachment portion160. The insertion tool attachment portion 160 may be positioned ateither and/or both of the ends 112,114. As shown in FIGS. 1 and 3 , theinsertion tool attachment portion 120 is positioned at the end 114.

The insertion tool attachment portion 160 may comprise recesses,grooves, bosses, holes, threads, posts or other features that can beused to secure the implant 100 to an elongated instrument. The implantin FIG. 3 utilizes a threaded hole 162 that may extend through one ormore walls at the end 114 along with one or more arm pockets 164.Together these features are configured to house the distal end of animplant inserter comprising an elongated shaft with a U-shaped end.Central to the U is a threaded rod for engagement into the threaded hole162 to pull the implant tight to the instrument. The arms of the U arespaced and configured to be received in the one or more arm pockets 164to control rotational stability and to limit bending stress on thethreaded rod from the instrument that threads into the threaded hole 162of the implant 100.

A further form of an implant is illustrated in FIGS. 9-12 . It should benoted that similar features found in this embodiment will be givensimilar numbers to those features previously described. Morespecifically, an implant 200 is provided having a body 202, a superiorface 204 and in inferior face 206. As most readily seen in FIG. 11 , thesuperior 204 and inferior 206 faces may include a gentle curvature. Thebody 202 also includes longitudinal ends 212,214.

Further, the faces may be configured and positioned such that the bodyis somewhat tapered. In this regard, a thin body portion 270 may be atend 212 while a relatively thick body portion 272 may be at the otherend 214. The body 202 may also include side walls 216,218. As shown inFIG. 11 , the body 202 generally tapers down from end 214 towards end212. Further, it should be noted that end 212 is somewhat beveled orotherwise arcuate, but need not be as beveled or arcuate as theembodiment shown in FIG. 1 as end 212 is a thin portion 270 that, as aresult of its shape and taper, will assist in distracting adjacentvertebrae. Therefore, end 212 may be inserted as a leading edge into apatient.

As seen in FIG. 11 , the end 214 is beveled, tapered, arcuate orotherwise configured to assist in distracting adjacent vertebrae. Inthis regard, the implant 200 may be considered a bi-directional implantas it may be inserted with either of end 212 or end 214 as the leadingedge during insertion as either end 212,214 will assist in distractingadjacent vertebrae. Just as with implant 100, implant 200 may take avariety of shapes, sizes, configurations and the like.

Further, implant 200 may also include cortical teeth 220 and centralteeth 222 similar to the manner and features described above withrespect to the embodiment of FIG. 1 . The cortical teeth 220 and centralteeth 222 may be configured and positioned in an osteo-specific mannerto provide interact with different bone materials and densities asdiscussed above.

The cortical teeth 220 include bone engaging ends 224 and valleys 226between the teeth 220 which may be used to help define a number ofdifferent rows 228 of cortical teeth 220. The central teeth 222 includebone engaging ends 230 which are sharper when compared to the boneengaging ends 224 of the cortical teeth 220. The sizes, shapes,positioning, functionality and other features of the cortical teeth 220and central teeth 222 may be similar to those described above withrespect to the embodiment of FIG. 1 .

The implant 200 may also include one or more throughbores 240 on aninterior wall 242 of the implant body 202. The througbores 240 mayinclude similar features, including protrusions 244 in a similararrangement and configuration as described above.

The implant 200 may include a longitudinal gap 274 in the thin bodyportion 270 open to the end 212. In this regard, the longitudinal gap272 may terminate at a transverse wall portion 276 that is intermediatethe longitudinal ends 212,214. Therefore, the longitudinal gap 272 maybe a generally U-shaped gap defined by the transverse wall portion 276and side arm portions 278. It should be noted that the transverse wallportion 276 is positioned away from the far-most portion of end 212 sothat the transverse wall portion 276 has a thickness greater than thethin body portion 270.

The implant 200 may include one or more insertion tool attachmentportions. As found in FIGS. 9-21 , the implant 200 includes twoinsertion tool attachment portions. A first tool attachment portion 260may be provided at end 214, similar to insertion tool attachment portion160. In this regard, the first insertion tool attachment portion 260 mayinclude a variety of different structures to couple to an insertiontool. For example, the first insertion tool attachment portion 260includes a threaded hole 262 and one or more arm pockets 264. The firstinsertion tool attachment portion 260 may be configured in a similarmanner to portion 160 described above and use a similar tool to therebyprovide end 212 as an insertion leading edge.

The implant 200 may also include a second insertion tool attachmentportion 290. In one form, the second insertion tool attachment portion290 may be located adjacent the transverse wall portion 276. In thisregard, the second insertion tool attachment portion 290 may beconfigured to couple to the same tool as with the first insertion toolattachment portion 260 or a different tool. In one form, the secondinsertion tool attachment portion 290 includes a threaded hole 292 andthe longitudinal gap 274 for receiving an insertion tool. The transversewall portion 276 and/or the side arm portions 278 may cooperate with theinsertion tool to stabilize the implant during insertion.

The implants may be configured to be cooperable with a number ofinstruments to allow a surgeon to implant and manipulate the implant.Exemplary forms of such tools are depicted in FIGS. 13-21 . In one form,a first insertion tool 300 is configured for cooperating with a firstend of the implant, such as end 212. A second insertion tool 302 may beconfigured to cooperating with a second end of the implant, such as end214.

In one form, the tools 300,302 are generally symmetrical in thehorizontal direction, though it may alternatively be asymmetrical sothat a particular relative orientation is required for coupling theimplant and the insertion tool 300,302.

The insertion tools 300,302 may be used to insert the implant within theintervertebral space, and may be used for manipulation of the implantwithin the intervertebral space. To enable this, a distal end 320,322 ofthe insertion tools 300,302 and the implant are coupled in a releasablefixed orientation. The insertion tool distal ends 320,322 and theimplant are coupled so that a surgeon may apply force to the insertiontool 300,302 without the implant separating therefrom.

Referring to FIGS. 13 and 17 , the insertion tools 300,302 have a handleportion 330,332 allowing a surgeon to manipulate the coupled implant 200and insertion tool 300,302. Extending from the handle portion 330,332 isa shaft portion 334,336 including a sheath portion 338,340 with thedistal ends 320,322 engageable with the respective insertion toolattachment portions of the implant 200. The sheath portions 338,340includes a longitudinal throughbore 342,344 in which a rod 346,348 isreceived. The rods 346,348 have an outer diameter sized to permit therod 346,348 to easily rotate or reciprocate within the throughbores342,344.

The insertion tool distal ends 320,322 are coupled with the implant 200by engaging the rod 346,348 and the distal end 320,322 in the respectiveinsertion tool attachment portions 260,290. For example, the rod 346 maybe coupled to the threaded hole 292 while the rod 348 may be coupled tothe threaded hole 262. The distal end 322 includes a pair of curved arms400 extending outward from the distal end 322 forming a crescent-likestructure which may be received by the arm pockets 264. The distal end320 may include arms 402 which may be configured to couple to thelongitudinal gap 274, the transverse wall portion 276 and/or the sidearm portions 278.

Due to the anatomy of a patient, it is common and desirable to implantintervertebral fusion devices from an anterior or posterior-lateraldirection, that is, from a direction offset from the lateral oranterior-posterior sides. The implant is inserted into theintervertebral space from this direction, and then the implant ismanipulated into the desired orientation during insertion of the implantinto the intervertebral space.

In one form, the implant is configured to lateral surgical entry. Forexample, in one form, the body of the implant has a height (H) which issized upon insertion to return the intervertebral disc spacing to aheight substantially the same as when spaced by a healthy intervertebraldisc. The device has a length (L) substantially the lateral width of thevertebral endplate. The device also has a width (W) that issubstantially less than the anterior to posterior length of thevertebral endplate and further sized for insertion down an elongatedcorridor to the surgical site.

The implant 200, which may be bi-directional, can be inserted fromeither end of the implant 200. For example, a patient having a deformityrequiring a coronal implant with first end 212 leading on one level andsecond end or trailing end 214 leading on adjacent level could placeboth implants from the same incision site. A coronal implant withinstrument attachment only at the second end or trailing end wouldrequire the surgeon to create a second incision on the contralateralside.

The implants described herein may also comprise additional features suchas one or more marker sites 180,280. In one embodiment, the marker sites180,280 may be in the form of a hole for the placement of a tantalummarker for viewing through X-ray or other imaging device. In thisembodiment the marker pin orientation confirms anterior/posterioralignment when a ‘T’ shape is made with the pins. These markers 180,280allow a surgeon to use radiographic equipment to identify the locationand orientation of the implant within the intervertebral space,including identifying the height, length, and width of the implant.Utilizing the radiographic markers, a determination can be made as towhether adjustments to the position of the implant are necessary ordesirable.

The implant devices described herein may be fabricated from any suitablematerials having desirable strength and biocompatibility. Suitablematerials may include, for example, biocompatible metals and relatedalloys (such as titanium and stainless steel), shape memory metals (suchas Nitinol), biocompatible polymers (including, for example, materialsof the polyaryletherketone family such as PEEK (polyetheretherketone),PAEK (polyaryletherketone), PEK (polyetherketone), PEKK(polyetherketoneketone), PEKEKK (polyetherketoneetherketoneketone),PEEKK (polyetheretherketoneketone), and PAEEK(polyaryletheretherketone), filled materials (such as carbon or glassfiber-reinforced materials), bone substitute materials (such ashydroxyapatite and tricalcium phosphate), composite materials, and/orany combination of the above.

In one preferred form, the implant devices are formed of a PEEK-typematerial. In another from, the implant device may be formed, in whole orin part, or coated with a calcium phosphate ceramic bone substitute suchas hydroxyapatite, tricalcium phosphate, and/or mixtures thereof.Particularly preferred hydroxyapatite and tricalcium phosphatecompositions include those disclosed in, for example, U.S. Pat. No.6,013,591, U.S. Pat. No. RE 39,196, and U.S. Patent ApplicationPublication No. 2005/0031704, which are hereby incorporated in theirentirety herein. Coating with the calcium phosphate ceramics can beachieved by any known method, including dip coating-sintering, immersioncoating, electrophoretic deposition, hot isostatic pressing, solutiondeposition, ion-beam sputter coating and dynamic mixing, thermalspraying techniques such as plasma spraying, flame spraying andhigh-velocity oxy-fuel combustion spraying. In one preferred embodiment,hydroxyapatite coating is achieved by plasma spraying.

In yet another form, the implant device may be formed of a PEEK-typematerial and coated with such a bone substitute material. In yet anotherform, the implant device may be formed, in whole or in part, coatedwith, injected with, incorporate, and/or retain a bone growthstimulating composition such as the bioactive hydrogel matrix described,for example, in U.S. Pat. Nos. 6,231,881, 6,730,315, 6,315,994,6,713,079, 6,261,587, 5,824,331, 6,068,974, 6,352,707, 6,270,977,5,614,205, 6,790,455, 5,922,339, and U.S. Patent Application PublicationNo. 2005/0118230, which are hereby incorporated in their entiretyherein. Alternatively, the implant device of the invention may be formedof two distinct materials.

As described throughout the present application, bone graft material,bone replacement material and the like may be utilized with the implantsto help fuse vertebrae. Exemplary artificial bone graft materialincludes calcium phosphates (such as hydroxyapatite and tri-calciumphosphate). Other suitable materials include those described in U.S.Pat. No. 6,013,591, J. Y. Ying, E. S. Ahn, and A. Nakahira,“Nanocrystalline apatites and composites, prostheses incorporating them,and method for their production,” which is incorporated by reference inits entirety herein. Another exemplary material is described in U.S.Pat. No. RE 39,196 E, Jackie Y. Ying, Edward S. Ahn, and AtsushiNakahira, “Nanocrystalline apatites and composites, prosthesesincorporating them, and method for their production,” which isincorporated by reference in its entirety herein.

Another exemplary product is described in U.S. Pat. No. 6,231,881 B1,Anton-Lewis Usala, and Richard Chris Klann, “Medium and matrix forlong-term proliferation of cells,” which is incorporated by reference inits entirety herein; and U.S. Pat. No. 6,730,315 B2, Anton-Lewis Usala,and Richard Chris Klann, “Medium and matrix for long-term proliferationof cells,” which is incorporated by reference in its entirety herein;and U.S. Pat. No. 6,315,994 B2, Anton-Lewis Usala, and Richard ChrisKlann, “Medium and matrix for long-term proliferation of cells,” whichis incorporated by reference in its entirety herein. Similarly, U.S.Pat. Nos. 6,713,079 B2, 6,261,587 B1, 5,824,331, 6,068,974, 6,352,707B1, 6,270,977 B1, 5,614,205, 6,790,455 B2, and 5,922,339 and U.S. PatentApplication 2005/0118230 A1, Ronald Stewart Hill, Richard Chris Klann,and Francis V. Lambert, “Methods and compositions for regeneratingconnective tissue,” are incorporated by reference in their entiretyherein. Further exemplary artificial bone graft materials are sold byPioneer Surgical Technologies, Inc., under the trade names E-Matrix,TrioMatrix, Nanoss and FortrOss.

It will be understood that various changes in the details, materials,and arrangements of parts and components which have been hereindescribed and illustrated in order to explain the nature of the methodsand compositions may be made by those skilled in the art within theprinciple and scope as expressed in the appended claims.

What is claimed is:
 1. An intervertebral implant for being implantedbetween adjacent vertebrae, the intervertebral implant comprising: agenerally elongate implant body extending along a longitudinal axisbetween longitudinal ends, and having an intermediate portion locatedbetween the longitudinal ends; a pair of spaced side walls extendinglongitudinally along the longitudinal axis; a lateral wall of theintermediate portion extending transverse to the longitudinal axis tospan a space between the spaced side walls so lateral end portions ofthe lateral wall are connected to the side walls; a superior face of theimplant body; an inferior face of the implant body; the superior faceand the inferior face being spaced such that the elongate implant bodyhas a varying height as the elongate implant body extends along thelongitudinal axis; one of the longitudinal ends being a tapered, noseend having a height less than that of the intermediate portion; theother longitudinal end being a tail end having a height less than thatof the intermediate portion and having a tool attachment portion formedtherein so that the intermediate portion has a height greater than boththe nose end and the tail end of the implant body; an interior surfaceof the implant body including an interior surface portion on one side ofthe lateral wall and an interior surface portion of the tapered, noseend that are spaced from and face each other, and first interior surfaceportions of the side walls that are spaced from and face each other andextend between the tapered, nose end and the lateral wall for receivingfusion material therebetween; the interior surface of the implant bodyfurther including an interior surface portion on another side of thelateral wall opposite the one side of the lateral wall and an interiorsurface portion of the tail end that are spaced from and face eachother, and second interior surface portions of the side walls that arespaced from and face each other and extend between the tail end and thelateral wall for receiving fusion material therebetween; a plurality ofprotrusions extending from the interior surface; and a plurality ofteeth on the superior and inferior faces in the intermediate portion. 2.The intervertebral implant of claim 1 wherein the implant body includesfirst and second throughopenings separated by the lateral wall.
 3. Theintervertebral implant of claim 2 wherein the first and secondthroughopenings do not communicate with each other at the superior andinferior faces of the implant body.
 4. The intervertebral implant ofclaim 2 wherein the lateral wall extends to the superior face and theinferior face to separate the first and second throughopenings from eachother.
 5. The intervertebral implant of claim 1 wherein the interiorsurface portions of the one side of the lateral wall and the tapered,nose end are longitudinally spaced from and face each other across afirst throughopening of the implant body, the first interior surfaceportions of the side walls are laterally spaced from and face each otheracross the first throughopening, the interior surface portions of theother side of the lateral wall and the tail end are longitudinallyspaced from and face each other across a second through opening of theimplant body, and the second interior surface portions of the side wallsare laterally spaced from and face each other across the secondthroughopening.
 6. The intervertebral implant of claim 1 wherein theplurality of teeth are positioned in rows on the superior and inferiorfaces surrounding at least a portion of the first and secondthroughopenings.
 7. The intervertebral implant of claim 6 wherein therows of teeth are defined by valleys between the rows.
 8. Theintervertebral implant of claim 1 further comprising an arm pocketpositioned on at least one of the longitudinal ends, the arm pocketconfigured to receive a portion of an insertion tool.
 9. Theintervertebral implant of claim 1 wherein the plurality of teethcomprise cortical teeth and central teeth.
 10. The intervertebralimplant of claim 9 wherein the cortical and central teeth have peakswith the central teeth peaks being sharper than the cortical teethpeaks.
 11. The intervertebral implant of claim 9 wherein each of thecortical teeth and central teeth include peaks with the central teethhave a greater spacing between adjacent peaks than the spacing betweenadjacent peaks of the cortical teeth.
 12. The intervertebral implant ofclaim 9 wherein the cortical teeth are arranged in a predetermined areaon each of the superior and inferior faces in a generally arcuateconfiguration.
 13. The intervertebral implant of claim 9 wherein thecortical teeth are arranged in a first density per unit area and thecentral teeth are provided in a second density per unit area that isless than the first density.
 14. The intervertebral implant of claim 1wherein the protrusions extend from the interior surface portion of thetapered, nose end, the interior surface portion of the tail end, and thefirst and the second interior surface portions.
 15. The intervertebralimplant of claim 14 wherein the protrusions extend from the one side andthe other side of the lateral wall.